This application requests funds for the purchase of a Zeiss LSM510 Meta confocal microscope. The eleven primary users of this instrument are faculty of the Department of Biology at the University of Rochester. These include a core group of 8 NIH-funded users and three additional users funded by the NSF and the NIH, respectively. The current programs of the users involve carrying out studies on the regulation of nuclear transport and genome packaging in yeast and Tetrahymena, molecular control of cellular growth and senescence, DNA repair and apoptosis in vertebrates and flies, regulation of neuronal specification in C.elegans, control of motor-driven transport of organelles in Drosophila and on the the role of the centrosome in asymmetric cell division in snails. These projects are unified in using molecular, genetic and biochemical techniques to ask how specific gene products influence cellular and developmental processes. In order to carry out quantitation, dynamic analysis and co-localization studies, all of these projects require access to a state-of-the-art confocal microscope which is (i) reliable and easy to use (ii) has superior resolution, scan speed and sensitivity, (iii) has multiple acquisition channels, (iv) includes a UV laser line for accurate detection of nuclear DNA. In addition, several of the projects will be dramatically enhanced by the ability to carry out spectral detections methods. The requested instrument will replace a first-generation confocal microscope that is currently present in a shared imaging facility of the department and that is reaching the limits of its useful lifetime. This facility has an excellent track record of care and maintenance of the current instrument, as well as of managing access of multiple users. [unreadable] [unreadable] [unreadable]